Steroid Withdrawal and Donor-specific Anti-HLA Antibodies in Renal Transplant Patients

Inclusion Criteria: 1. Male and female patients aged over 18 years with no immunological risk (PRA \<25% and no DSA) who are receiving their first cadaveric or living kidney transplant. 2. Patients who, three months after the transplantation, are receiving tacrolimus in combination with mycophenolic acid (MPA) or mycophenolate mofetil (MMF) plus steroids, with stable plasma levels of tacrolimus. 3. No clinical or histological immunological dysfunction before randomization 4. No de novo anti-HLA DSA at the time of randomization. 5. Patients who wish to and are able to give written informed consent to participate in the study. 6. For women, agreeing to use efficient contraception during the study. Exclusion Criteria: 1. Patients who receive a multiorgan transplant. 2. Retransplants. 3. Presence of DSA before the transplant or at the time of randomization. 4. Cold ischemia time \>30 hours 5. Patients with serum creatinine \>2 mg/dL or proteinuria \>1g/day at the time of randomization 6. Prior episode of severe rejection (II-B-III in the Banff/13 classification) prior to randomization. 7. Presence of subclinical rejection on the protocol biopsy prior to randomization 8. Patients with BK-polyomavirus nephropathy at the time of randomization. 9. Patients with recurrent or de novo glomerulonephritis. 10. Patients who are being treated with immunosuppressive drugs other than those in the randomized clinical trial in question. 11. Patients who are positive for the human immunodeficiency virus (HIV) or those who have a severe systemic infection that, in the investigator's judgment, will require continued treatment. 12. Patients with any present or prior (during the previous 5 years) malignant disease, except basal or squamous cell carcinoma that has been excised.